Back to back cargo deliveries mark busy week aboard ISS. Two different cargo ships arrived at the International Space Station this week, each returning their respective vehicles to flight status following accidents and setting new historic milestones. On Wednesday, February 22, a SpaceX Dragon spacecraft with 5,473 pounds of cargo arrived at the complex on the CRS-10 mission. Dragon launched February 19 on what was the first post-shuttle use of the historic LC-19A launch pad at Kennedy Space Center. CRS-10 was the first SpaceX launch from Florida since the Amos-6 accident in September 2016, destroyed their primary launch complex, SLC-40. Less than a day later, on February 23, Progress MS-05 arrived with 5,401 pounds of cargo following its launch from Baikonur Cosmodrome. MS-05, known as 66P in the ISS vehicle manifest, marked the final launch of the Soyuz-U rocket, a variant of the historic rocket that has made 786 flights since 1973. The modern Soyuz-2 rocket rendered the Soyuz-U variant obsolete in 2015. Progress MS-05 was the first Progress flight since the December 1 2016, launch failure of Progress MS-04. P/C: Thomas Pesquet/ESA, Andrei Borisenko/Roscosmos. Below: A NASA diagram showing the visiting vehicles attached to the International Space Station. 

Final Progress flight of 2016 ends in failure; spacecraft crashes on Earth.

For the second time in 18 months, a Soyuz rocket carrying an unmanned Progress cargo freighter to the International Space Station suffered a malfunction resulting in a mission failure.

Liftoff of Progress MS-04 occurred at 9:51am EDT from the Baikonur cosmodrome in Kazakhstan. The early stages of the flight were nominal, but as the Soyuz rocket's Blok I third stage was firing, telemetry between the vehicle and ground stations became “ratty” according to NASA voice commentary. It was also unclear is the spacecraft's solar arrays had deployed, a key indicator that it was safely in orbit.

Within an hour of launch, reports from Russia's Tuva region reported large pieces of debris and explosions coming from the sky followed by ground tremors, likely indicating the spacecraft and its upper stage. Roscosmos confirmed that Progress was indeed lost and destructively fell through the atmosphere.

Among the 2.5 tons of cargo the unmanned cargo freighter was delivering to the station was a new, upgraded Russian Orlan EVA suit and an experimental water recycling experiment.

It is currently unknown what caused today's anomaly, though this is the third mission-ending malfunction of a Progress flight during the operation of the Blok I third stage. A mishap in 2015 between the spacecraft and its interface with the third stage caused Progress M-27M to tumble out of control, eventually burning up two weeks after launch. An earlier malfunction in 2011 on Progress M-12M caused by a blocked fuel line in the third stage caused the spacecraft to crash in eastern Russia. The Blok I stage of both rockets are similar, though the stage for the modern Soyuz-2-1a features some modifications and upgrades.

While last year's mishap used a newer variant of the historic launcher, the Soyuz 2-1a, today's flight occurred on a Soyuz-U model. It was the penultimate flight of that variant of the rocket, which was first introduced in 1973. Its final flight is expected to occur in February, 2017, with the Progress MS-05 mission. Blok I comparison between the older Soyuz U and modern Soyuz 2-1a rockets. The 2-1a features upgraded avionics, a stretched Liquid Oxygen tank, and other modifications. (P/C: RussianSpaceWeb)